7.2 Soil Formation and Composition

Vocabulary


Soil: Weathered and loose material on the Earth's surface in which plants can grow in.
Bedrock: The bedrock is the solid block of rock beneath the soil.
Humus: A very dark-colored substance that forms when animals and plants decay.
Loam: Soil that is made out of equal amounts of clay, sand, and silt.
Soil Horizon: A soil layer that differs in color and texture from the layers that are above the soil or below the soil.
Topsoil: Crumbly, dark brown soil that is a mixture of humus, clay, and other materials.
Subsoil: A soil layer that consists of clay and other particles washed down from the soil horizon.
Litter: A loose layer that forms when plants shed their leaves.
Decomposers: Organisms that break the remains of dead organisms into smaller pieces and then digest them with chemicals.

Outline